EXAM III

Hydroxyl

A functional group (-OH) that is polar and hydrophilic.

Carboxyl

A functional group (-COOH) that is acidic and polar.

Amino

A functional group (-NH₂) that is basic and polar.

Phosphate

A functional group (-PO₄³⁻) that has a negative charge and is polar.

Methyl

A functional group (-CH₃) that is nonpolar and hydrophobic.

Dehydration Reaction

A process that removes H₂O to build molecules, which is endergonic.

Hydrolysis Reaction

A process that adds H₂O to break molecules, which is exergonic.

Monosaccharide

A type of carbohydrate that consists of one sugar (e.g., glucose).

Disaccharide

A type of carbohydrate that consists of two sugars (e.g., sucrose).

Oligosaccharide

A type of carbohydrate that consists of a few sugars.

Polysaccharide

A type of carbohydrate that consists of many sugars (e.g., starch, glycogen).

RNA Bases

The bases in RNA are A, U, C, and G.

DNA Bases

The bases in DNA are A, T, C, and G.

Cofactor

A helper molecule (often a metal ion) for enzymes.

Activator

A substance that speeds up enzyme activity.

Inhibitor

A substance that slows or stops enzyme activity.

ATP Cycle

The process involving ATP converting to ADP + P to release energy and ADP + P converting back to ATP to store energy.

Phospholipid Bilayer

The structure formed by phospholipids in water, with hydrophilic heads outward and hydrophobic tails inward.

Autotrophs

Organisms that make their own food (e.g., through photosynthesis).

Heterotrophs

Organisms that consume food to gain energy.

Oxidation

The process of losing electrons.

Reduction

The process of gaining electrons.

Electrochemical Gradient

The difference in charge and concentration of ions across a membrane.

Glycolysis

The first stage of cellular respiration occurring in the cytoplasm that converts glucose to pyruvate, yielding 2 ATP.

Citric Acid Cycle

The second stage of cellular respiration that occurs in the mitochondria, producing electron carriers like NADH and FADH₂.

Oxidative Phosphorylation

The final stage of cellular respiration that produces 26-28 ATP through the electron transport chain.

Feedback Regulation

Processes that maintain balance in metabolism through negative or positive feedback.

Chemiosmosis

The process where ATP synthase utilizes the H⁺ gradient to produce ATP.

Fermentation

A metabolic process that occurs in the absence of oxygen, regenerating NAD⁺ to allow glycolysis to continue.

Coupled Reactions

The mechanism where energy from exergonic reactions powers endergonic reactions.

Phosphorylation

The addition of a phosphate group to a molecule, often to activate or deactivate enzymes.

Electronegativity

The tendency of an atom to attract electrons, with oxygen being highly electronegative.

5’ vs 3’ End

The directionality of nucleic acids where 5' end is phosphate and 3' end is OH group.

Antiparallel Strands

The orientation of DNA strands where one runs 5’ to 3’ and the other runs 3’ to 5’.

ATP Synthase

An enzyme that creates ATP from ADP and phosphate, driven by a proton gradient.

Saturated vs Unsaturated Fats

Saturated fats have no double bonds and are solid at room temperature, while unsaturated fats have double bonds and are liquid.

Membrane Transport

The movement of substances across cell membranes, which can be passive or active.

Micelles

Spherical structures formed when phospholipids are in water.

Biological Energetics

The study of how energy flows through living systems, from food/light to ATP.

Substrate-level Phosphorylation

The direct production of ATP in pathways like glycolysis and the citric acid cycle.